N-Heterocyclic Carbene-Catalyzed Decarboxylative Cross-Electrophile Coupling to Access Sterically Hindered Ketones

Abstract

Although radical NHC (nitrogen-heterocyclic carbene) catalysis has emerged as a powerful strategy for constructing carbon-carbon (C-C) bonds to generate value-added ketones from carbonyl compounds including carboxylic acids and aldehydes, great advances were generally focused on the redox-neutral NHC catalysis and oxidative NHC catalysis until now. Cross-electrophile coupling reactions as powerful tools for forming C-C bonds avoiding using preformed carbon nucleophilic organometallic reagents have not been well developed by radical NHC catalysis. Here, we demonstrate that nitrogen-heterocyclic carbene (NHC), in conjunction with manganese (Mn), can promote the cross-coupling of aromatic acids or derivatives with a wide array of broadly available electrophiles to deliver various sterically bulky ketones with high yields. In addition, its utility in the concise synthesis of biologically active compounds is further highlighted.